1. Field Of The Invention
This invention relates to a process for the production of substituted aryl sulfides. More particularly, this invention relates to a process for the production of alkanoylamino or (N-alkyl)alkanoylamino substituted aryl sulfides, such as bis(p-acetylated amine) substituted diaryl sulfides, by employing an alkali metal tetrafluoroborate catalyst.
2. Background Of The Invention
A wide variety of aryl sulfides, and in particular diaryl sulfides, are known, the utilities of which are just as varied. For example, aryl and in particular diaryl sulfides are known to be useful as intermediates, especially for the preparation of insecticides, as plasticizers, high boiling solvents, heat exchange fluids, and hydraulic fluids.
A well-known class of substituted diaryl sulfides is that of the hydroxy substituted diaryl sulfides, or thiobisphenols, same generally finding utility as intermediates or as oxidation inhibitors. One generally known process for preparing hydroxy substituted diaryl sulfides, or thiobisphenols, is by reacting a phenol with a sulfur chloride compound.
For example, U.S. Pat. No. 4,056,568 discloses the reaction of a 3,5-dialkyl phenol with a sulfur chloride compound to form a sulfenyl chloride. Subsequent reaction thereof with a phenol produces a diaryl monosulfide.
U.S. Pat. No. 3,718,699 discloses a process of preparing 4,4'-dithiobis(2,6-di-t-butylphenol). Said process comprises reacting 2,6-di-t-butylphenol with sulfur monochloride in the absence or presence of a catalytic amount of iron powder or a Lewis acid.
U.S. Pat. No. 3,129,213 discloses a process wherein an orthoalkylphenol is reacted with sulfur dichloride to form a reaction product suitable for use as an antioxidant and/or antiwear agent. U.S. Pat. No. 3,057,926 discloses a process wherein an alkyl or alkoxy substituted phenol is reacted with sulfur dichloride. Alternatively, the process may comprise the reaction of an alkali metal salt of the substituted phenol with sulfur dichloride. Neither reaction, however, is conducted in the presence of a conventional catalyst.
Similarly, U.S. Pat. Nos. 2,139,321; 2,370,756; and 2,971,968 disclose the preparation of thiobisphenols by reacting an alkyl phenol with a sulfur chloride compound in the absence of a catalyst.
U.S. Pat. No. 2,402,685, however, discloses reacting a phenol with sulfur dichloride in the presence of a "sulfurization catalyst" to produce a diaryl monosulfide product. Examples of suitable "sulfurization catalysts" include aluminum chloride, bismuth chloride, iron chloride, mercuric chloride, tin chloride, antimony chloride, tantallum pentachloride, titanium tetrachloride and zinc chloride.
While numerous processes are thus known for preparing hydroxy substituted aryl sulfides, the prior art is devoid of a truly suitable process for the formation of aryl sulfide compounds, and in particular diaryl sulfides, wherein the aromatic rings are substituted, particularly in the para positions, with a more complex electron releasing group, such as an alkanoylamino substituent, e.g., an acetylated amine. Such a process, especially if given to high reaction rates and yields, would find ready acceptance by the industry for the preparation of such compounds, which find utility as aromatic monomers, precursors, epoxy curing agents, cure accelerators, etc.
Accordingly, it is an object of the present invention to provide a novel process for preparing substituted aryl sulfides, and in particular, alkanoylamino and (N-alkyl)alkanoylamino substituted aryl sulfides, in good yields and at a high reaction rate.
It is another object of the instant invention to provide a novel process for the production of substituted diaryl sulfides, and in particular, diaryl sulfides substituted in the para positions with an acetylated amine.
Another object of the instant invention is to provide an effective process for synthesizing a bis(p-acetylated amine) diaryl sulfide via a coupling reaction.
Still another object of the instant invention is to provide a process for producing sulfides in high yields, with high reaction rates, and with high selectivity.
These and other objects, as well as the scope, nature and utilization of the invention, will be apparent to those skilled in the art from the following description and the appended claims.